a company is only worth there salt if they professionally wire, and use aftermarket paste anyways, Also your better off with a hyper212+ than any closed loop watercooling. Also worth noting for a gaming computer you wont see a difference between i5-2400k and any other higher end proc so save a few bucks.
If you want to save even more, try Custompcandrepairs.com. They do custom systems like these. I have bought my last 2 from them, and they are great. send em an email and at least get a price quote or something.
BUILD IT BUILD IT BUILD IT!!!! In the last 9 years i have bought 3 computers. 1 from CP, built one, and custompcandrepairs was my last one. I saw good posts on here about them so i tried them. Building it myself was the mot satisfying, yet time consuming. CP was nothig but a headache with a mediocre product, and custompcandrepairs was the easiest most hassle free way. Building it yourself will be a little cheaper but not by much.